Additive manufacturing devices produce three-dimensional parts from feedstock by, according to part creation instructions, sequentially adding materials to a part being formed. Additive manufacturing enables quick, easy, precise, and repeatable creation of a variety of objects.
Fused filament fabrication additive manufacturing devices, also known as fused deposition modeling printers, create parts via depositing melting filament in a raster pattern. Such devices can generally only produce parts having a resolution of 150 to 300 microns at sizes fewer than two feet per side. At such scales, part creation times are significant due to the raster movement of the filament extruder. Furthermore, such filaments are not suitable for well-known techniques such as lost wax casting and also produce a part which is prone to losing portions of itself due to strands of filament coming off because of poor bonding between adjacent strands of filament.
Photopolymer-based additive manufacturing devices are capable of generating parts having a higher feature resolution, often measured in the 10s of microns. Such parts may also be used in lost wax casting processes. Photopolymer-based additive manufacturing devices typically comprise a movable build plate, a controllable light source, a photopolymer supply (e.g., a vat of photopolymer) and a build area where photopolymer from the photopolymer supply is selectively cured, forming portions of the part being created. The part is connected to the build plate as it is created. Each newly created portion of the part (e.g., a layer) adheres to the build area as it is created, necessitating separation of the part from the build area by applying a separation force. This may be accomplished by peeling, pulling, sliding or other movements. In some cases, the separation force is strong enough to distort or destroy fragile portions of a part because the fragile portion is stretched, strained, and even completely separated from the part as the part is repositioned to form the next layer of the part. Because this separation force destroys or damages fine detailing in a desired part design, quality is limited.
Each newly formed layer must be separated from the build area surface before additional photopolymer material may be deposited (by flowing, deposition or otherwise supplying the material), exposed to electromagnetic radiation and added to the part. Bonding and/or vacuum forces may connect the newly formed portion of the part to the build area surface. These forces must be overcome in a manner which does not damage the part being created, thereby establishing a minimum feature size and maximum print speed.
Many prior art additive manufacturing devices use either at least a slide motion or tilt motion to release a part being built during the build process to separate it from a build table so that a next layer to the part may be applied. These motions are required to minimize destructive forces on the part being built. One known prior art approach uses both a lift and slide motion that occurs at a same time, or simultaneously, to assist in release of the part from the build table. Providing any of these motions requires an additional powered release mechanism to be a part of the additive manufacturing device and increases the length of time required to form the part.
Pulling a part being formed vertically upward from a build area is known and a need for an additional powered release mechanism is not needed. Prior art attempts to only vertically lift the part have proven to take longer when compared to employing a slide or tilt motion. How far to lift the part and at what rate to lift the part to reliably produce a part are unknown. To compensate, such prior art systems that utilize vertical lift only compromise to avoid damage by providing a slow lift rate to a high height to ensure no damage occurred where rate and height are static for any part build.
Though the additive manufacturing process described above is considered rapid manufacturing, there are several inefficiencies in the process and known additive manufacturing devices which could be improved upon to further enhance the processing speed. Given the foregoing, users of such devices would benefit from an additive manufacturing device which facilitates a more rapid and efficient operation that would result in improved manufacturing time.